Surgeons want better hip implant monitoring

  • Niall Hunter, Editor

Irish orthopaedic surgeons want a joint replacement register set up in Ireland to monitor the effectiveness and safety of Hip and other artificial joint replacements.

Mr David Moore, President of the Institute of Orthopaedic and Trauma Surgery says the Institute has called on the HSE to agree to a joint replacement register which would give better data on artificial hip and other joint replacements and any problems that might be emerging with them.

In August, the DePuy ASR hip implant system was withdrawn from the market after reports of a higher than normal failure rate with the device, and 3,500 Irish patients who received the implant are being reviewed.

However, concerns have also emerged about possible problems with all metal-on-metal (MoM) devices and not just the DePuy metal-on-metal ASR device.

Up to 400 people who received the DePuy product may require new hip replacement operations. Recent research found that after five years, around 12% of people who received this implant needed it replaced.

Earlier this year prior to the De Puy recall and patient review, a UK regulatory body issued a medical device alert about all metal-on-metal (MoM) hip replacements, of which the De Puy ASR is just one of the replacement hips used, and this warning was passed on to orthopaedic surgeons in Ireland by the Irish Medicines Board (IMB).

In April, the Medicines and Healthcare Products Agency (MHRA) in the UK called on surgeons to put systems in place for the follow-up of patients implanted with all MoM replacements, after it received reports of revisions of MoM replacements involving soft tissue reactions. These reactions may be associated with unexplained hip pain, the agency said.

The MHRA stressed that the incidence of pain or swelling following MoM hip implants is very uncommon, but said it would continue to review individual types of MoM hip replacements and if necessary, will issue further advice accordingly.

However, Ireland does not have such a monitoring system for artificial hip implants.

David Moore said to date, there is no evidence in Ireland of major issues with other MoM hips, but admitted the evidence of this is essentially anecdotal.

He said the Institute was in discussion with the HSE about setting up a joint replacement register in Ireland. This would for the first time give detailed data on the different type of hip implants used, revision rates for implants,and  any problems that might be emerging, in order to provide early warning signals about such problems.

Mr Moore said the register, which could be run by the Royal College of Surgeons in Ireland with the HSE, would act as a centralised data source where all hips and other joint replacements inserted in patients would be compulsorily registered and monitored.

At present, Ireland relies on on registers from other countries to identify joint replacement problems, and it was data from the UK joint register that led to the worldwide alert to the problems with the DePuy hip product.

Mr Moore said the UK alert on all MoM hips in April would have raised the level of suspicion, but there had been no reports to date as far as the Institute was aware, of problems with other metal-on-metal implants of the scale of those reported with the DePuy implants.

He stressed that even the most successful hip replacement will eventually have a failure rate of 15% after 35 years. The problem with the DePuy ASR device was that the rate was 13% after only five years.

Asked if Irish surgeons would now be reviewing all patients with MoM implants following the UK alert in April, Mr Moore said in the normal course of events, all patients with MoM implants would be reviewed regularly by their consultants and followed up if any problems emerged.

However, he admitted that one of the problems was that we do not know for certain about the efficacy of any hip replacement in Ireland, nor do we have centralised data about hip replacements, and this was why a register was needed.

Asked whether in view of the UK device warning which was subsequently given to Irish surgeons, all patients who had MoM implants should be reviewed for possible adverse effects, the Irish Medicines Board told all patients with hip implants are regularly monitored by their orthopaedic surgeons.

"The majority of patients implanted with MoM hip replacements have well functioning hips and are thought to be at a low risk of developing serious problems."

The IMB said the UK alert provided specific advice to surgeons on the management of patients with MoM implants, in particular the types of test that should be considered for patients presenting with painful hip implants.

It said the guidance provided in the alert was of a general nature, and did not refer to any particular manufacturer's product.

In a letter from the IMB to orthopaedic surgeons in early May, the Medicines Board notified them of the UK alert on MoM devices.

It said while the UK MHRA considered that the majority of patients given MoM implants have well-functioning hips and are thought to be at low risk of developing serious problems, a small number of patients may develop progressive soft tissue reactions to the wear debris associated with the implants.

"The debris can cause soft tissue necrosis and adversely affect the results of revision surgery. In line with this, early revision of poorly-performing MoM hip replacements may give a better revision outcome," the IMB said.



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